1. Field of the Invention
The present invention relates generally to material processing and more particularly, to a method of preparing pure pearl powder.
2. Description of the Related Art
Pearl is a noble Chinese medicine. According to modern scientific searches, pearl contains various amino acids including Asp, Thr, Ser, Glu, Gly, Ala, Gys, Val, Met, Ile, Leu, Tyr, Ph., Lys, His, Arg, Pro, Taurine and etc. Pearl also contains many minor elements necessary for human body such as Fe, Zn, Cu, Co, Mn, Cr, Se, I, Ni, F, Mo, V, Sn, Sr, Ge, and etc. Pearl is effective in tranquilizing the mind, improving eyesight, detoxifying chemicals and promoting granulation. It is a good for anti-aging beauty and healthcare applications. However, pearl is a mixed organic-inorganic nanostructured material, comprising two layers of calcium carbonate of aragonite structure and a layer of protein of thickness ranging from several nanometers to ten and more nanometers sandwiched between the two layers of calcium carbonate. Therefore, pearl has the characteristics of high hardness and toughness. Processing of pearl is not easy. Conventionally, there are two ways to process pearl, i.e., the dry grinding method and water-adding grinding method. Pearl powder obtained by the method dry grinding has a relatively greater grain size about several tens of nanometers in diameter that is not effective for absorption in human body. Further, this pearl powder processing method cannot remove heavy metal and other impurities. The water-adding grinding method can remove impurities, however it is not suitable for industrial production because of the drawbacks of high consumption of energy and time during processing.